Add gabor filter function
Fix meshgrid bug in gabor kernel and argument passing
Add test cases for gabor filter
Add example script for gabor filter
Remove unnecessary kernel description for filtering
Merge pull request #477 from JDWarner/convert_dtype_to_astype

Use `image.astype(dtype)` instead of `dtype(image)`
be consistant with python implementation
improve unittests
Fix and improve example
Fix docstring
minor doc improv.
doc, minor improv.
big clean-up!
fix names
fix signature
cosmectics (flake8)
fix deprecated variable
Merge pull request #480 from sciunto/hl_review

Hough transoform: review
fix rank filters for float structuring element
Create dummy WindowsError that is an actual Exception instead of None. The previous solution prevented installation on py3.3 and OSX 10.6.1.